Coca-Cola League One leaders Leicester could manage only a 1-1 draw with Stockport as Peterborough moved into second place with a win at Leyton Orient on Tuesday.
Leicester scored after 65 seconds through Kerrea Gilbert. But the visitors responded just a minute later, former Foxes player Chris O'Grady slotting the ball past debutant goalkeeper David Stockdale.
The result maintained Leicester's 12-point advantage at the top. But it is now Peterborough who lead the chasing pack, Darren Ferguson's side hanging on for a 3-2 victory over Leyton Orient which moved them above MK Dons into the second automatic promotion spot.
Millwall consolidated their play-off position by halting Southend's good run of form with a 1-0 win at Roots Hall. Gary Alexander scored the winner on 39 minutes to move the Lions into fifth place at the expense of Leeds, who could only draw at fellow promotion rivals Oldham on Wednesday.
Scunthorpe missed their chance to overtake Leeds after being held to a 1-1 draw at home to Walsall. The Iron looked set for victory when Kayode Odejayi headed in with a little over 10 minutes to go - but five minutes later, Troy Deeney equalised to leave the match all square and Scunthorpe still a point outside the play-off places.
Tranmere's promotion push faltered with a 2-1 defeat at Hartlepool, Michael Nelson (69) and a penalty from Ben Clark (83) securing the points for Pool either side of a strike from Ben Chorley (70) in a late flurry of goals at Victoria Park.
Bottom club Cheltenham showed spirit on the day their manager announced the entire squad was up for sale, holding struggling Swindon to a 2-2 draw at the County Ground.
Crewe remain in trouble a point from the drop zone, after they were defeated 2-1 at home by Carlisle. Substitute Joe Anyinsah (73) gave the visitors all three points after goals in the first half from Gareth Taylor (17) and Clayton Donaldson (34).
Elsewhere, Huddersfield and Colchester drew 2-2 at the Galpharm Stadium - Dean Hammond adding to his first half penalty (19) by scoring an injury-time equaliser for the Us to cancel out strikes from Anthony Pilkington (51) and Gary Roberts (66).
MK Dons' match with Northampton was abandoned at half-time because of a waterlogged pitch, with the score at 0-0 while Yeovil's match with Hereford and Bristol Rovers' encounter with Brighton were both postponed for the same reason.
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